Sheet metal may be economically fabricated into a wider range of useful products including chassis for appliances and electrical devices. Turret-type punch presses have found wide use in fabricating sheet metal. Turret-type punch presses employ an upper, generally cylindrical turret which holds a series of punch tools spaced circumferentially around its periphery, and a second, lower turret holding a series of dies circumferentially spaced about that turret's periphery, each turret being rotatable about a vertical axis to bring an appropriate punch and die pair into vertical alignment at a work station. By appropriately rotating the two turrets, an operator can bring a number of punches and dies sequentially into alignment at the work station to perform a series of sequential and different punching operations on a work piece.
Repeated use of a punch assembly in a punch press operation results in the natural dulling and wear of the punch tip. Once the tip has become dull, the effectiveness of the punch assembly is reduced and the punch tip must be sharpened. Sharpening may be accomplished by grinding the end of the punch tip, and this results in shortening the length of the punch. The length of the punch may then be adjusted to compensate for the ground-off portion.
The longitudinal axis of the punch assembly is typically placed in coaxial alignment with the axis of the ram. The ram of the punch press then strikes the punch with great force on it's impact surface.